Last year research in Spain suggested that tetrahydrocannabinol (THC), marijuana’s psychoactive ingredient, kills brain cancer cells. Study coauthor, Guillermo Velasco of the Department of Biochemistry and Molecular Biology at Complutense University Madrid, Spain claims that when THC was applied to cancerous brain tissue, the cancer cells were destroyed while healthy cells were left alone.

Cannabidiol, (CBD), also found in marijuana, apparently does the same; a pair of scientists from California Pacific Medical Center in San Francisco demonstrated the cannabinoid’s ability to stop metastasis in many kinds of aggressive cancer.

“It took us about 20 years of research to figure this out, but we are very excited,” said Pierre Desprez, one of the scientists behind the discovery, to The Huffington Post. “We want to get started with trials as soon as possible.”